Humanity's first 161 years in space proved something of a honeymoon period. Advancements in hypersleep and faster-than-light travel propelled us out into the cosmic ocean, but we found only lonesome gulfs and ragged worlds. We triumphed in the discovery of rudimentary life-forms but discovered nothing to rival our own divine image.

Then, in A.D. 2122, everything changed. The crew of the USCSS Nostromo boarded a derelict vessel on the moon LV-426. There, members of the crew encountered what one observer dubbed "the perfect organism."

Of the derelict's original passengers, the Nostromo contingent found only petrified remains, but life still brooded deep in the vessel's cargo hold. There the doomed crew discovered a cache of leathery eggs -- eggs that would spawn humanity's initial encounters with the organism we now know as the xenomorph. The term, borrowed from geology, literally means "strange form," and certainly, this extraterrestrial defies easy understanding or classification. Much of its biology is analogous to terrestrial life, while other features remain a mystery.

Life on earth is cruel. Life on other worlds, as it turns out, is even crueler.